The eyes and the visual system
The eyes and the visual system
Facial features of CdLS are similar in both adults and children. Some individuals with CdLS may have facial features that make them seem older than their actual age. Eyebrows meeting in the middle, thick eyebrows and long eyelashes are very common in individuals with CdLS. They are considered hallmark features of the syndrome.
Ptosis (inability to fully open the eyes) is also common and can occur in one or both eyes (26,97,98). If an individual’s vision is significantly affected by ptosis, surgical correction can be considered, particularly if the individual is lifting their chin in attempt to see more clearly and it is affecting the individual’s ability to move around. Surgical correction should also be considered if ptosis has caused a lazy eye or vision to become blurry (R36).
Blepharitis is also common in CdLS. It is a condition where the eyelids become infected and swollen. Symptoms can include excessive watering of the eye, recurrent conjunctivitis, crusty eyelashes, small lumps on the eyelid and itchy red eyelids. These symptoms can be bothersome, particularly for young children (97,99). Blepharitis in CdLS can be treated in the same way as in the general population. Treatment includes eye lid hygiene using baby shampoo or eyelid scrubs (R37). If symptoms of blepharitis do not improve with lid hygiene, one or both tear ducts may be blocked or obstructed (R41). Blocked tear ducts can be treated using a surgical probing and irrigation procedure. Surgical probing and irrigation unblock the tear ducts and should be considered if other treatment for blepharitis is not successful (97,98).
Individuals with CdLS often experience visual impairment (3,41,98). Usually, individuals with CdLS are short-sighted (myopia). This means that distant objects appear to be blurry whilst close objects can be seen normally. Far-sightedness is less common in CdLS (98). Short-sightedness and far-sightedness are not eye diseases or eye health problems, they are simply a problem relating to how the eye focuses light. Individuals with CdLS may also have astigmatism, in which the outer layer of the eye is curved, causing blurred vision.
Vision should be assessed regularly in all individuals with CdLS, especially in infancy and childhood (R38). Correction of short-sightedness, far-sightedness or astigmatism should be performed as early as possible to prevent lazy eye. Children may have difficulty tolerating glasses or contact lenses, especially as self-injurious behaviour in CdLS may include hitting, pressing or poking the eyes. Surgical procedures, such as laser eye therapy, can help to improve visual function (100).
Some individuals with CdLS have been reported to have abnormal optic nerves (98). Another finding is a ring of pigment found around the optic nerve, seen on an eye exam in over 80% of children with CdLS, although this does not cause any harm. There is risk for retinal detachment in CdLS, either due to very severe near-sightedness or self-injurious behaviour relating to poking the eye.
A small number of individuals with CdLS may have nystagmus (rapid, involuntary eye movements) or strabismus (where one eye looks directly at the object they are viewing, while the other eye is misaligned) (97,98). In the case of strabismus in CdLS, strategies for the general population should be followed.